OS X: "An internal FaceTime error occurred" alert after clicking FaceTime icon in the Dock
When opening FaceTime from the Dock, the following alert message may appear:
"An internal FaceTime error occurred.
There was a problem with FaceTime. You need to quit and open FaceTime again."
OS X Mountain Lion
Download and install OS X Mountain Lion v10.8.4 or later.
OS X Lion
Click the FaceTime icon in the Dock one time, then wait for the application to finish opening.
This can happen if you attempt to open FaceTime a second time while it is already loading, such as by clicking the FaceTime Dock icon more than once.